I am an up-grader to. I loved what X cameras equipped with X-Trans can do, so for me the choice was obvious. I chose M1 for its size and uncompromized IQ. M1 did not disappoint. Love the colors, love the white balance, love the low light performance. No headaches whatsoever. All minor issues easily solved by Capture One or Iridient Developer. Just happy with my M1. Hope it shines a light on what other up-graders might think.For me it is heard to overestimate how important size is when it comes to capturing those precious moments in life. I keep my X-M1 always with me. This is a key asset for me. The camera fits in my briefcase. Even E-1 wouldn't. I could afford E1 or E2, but I did not view M1 as a downgrade. With it I can do something what I can't do with other X comers and this something is simply keeping your camera at hand at all times. Inspiration is a wonderful, but unpredictable thing. When it comes I prefer having at hand a camera without VF rather than a DSLR or other larger camera sitting like a dumbbell at home or in my car. Just as long as IQ is not compromised and with M1 it is not. Uncompromized IQ in a small package is an extremely valuable, though underestimated asset.